Machine gun cooling system



G. A. HAWKINS MACHINE GUN COOLING SYSTEM June 28, 1960 a Sheets-Sheet 1 Filed D60. 19. 1947 EEDIHE A-Hnwl4ina June 28, 1960 G. A. HAWKINS 7 4.

MACHINE GUN COOLING SYSTEM Filed Dec. 19, 1947 8 Sheets-Sheet 2 ixzracfor cam INVENTOR.

Gem-gs AHamKins BY June 28, 1960 G. A. HAWKINS 2,942,524

MACHINE GUN COOLING SYSTEM I Filed Dec. 19. 1947 8Sheets-$heet :5

EU N George A-Huw]:in5

June 28, 1960 G. A. HAWKINS MACHINE GUN COOLING SYSTEM 8 Sheets-Sheet 4 Filed Dec. 19, 1947 E ears e A.H'uwKi'n .5

June 28, 1960 e. A. HAWKINS MACHINE cum COOLING SYSTEM 8 Sheets-Sheet 5 Filed Dec. 19. 1947 5 7 2 m w 5 E W //Y///////w\///// F////// II II I I II I. 4 v w Gan r52 A H'n wK-i-ns June 28, 1960 I G. A. HAWKINS MACHINE GUN coouuc SYSTEM 8 Sheets-Sheet 6 Filed Dec. 19. 1947;

June 28, 1960 G. A. HAWKINS MACHINEGUN COOLING SYSTEM I 8 Sheets-Sheet '7 Filed Dec. 19. 1947 NSN WNW gvwc/rytm B E 13132 A- Huwkirus Jung 28, 1 960 G. A. HAWKINS MACHINE GUN coouuc SYSTEM 8 Sheets-Sheet 8 WWA Filed Dec. 19. 1947 v v F /////////////m/// George A-Huwl4in.s

Gum/M m; HT HILH MACHINE GUN COOLING" SYSTEM George A. Hawkins, Lafayette, lnd., assignor, by mesne assignments, tothe United States of America as represented by the Secretaryof the Army 7 Filed Dec. 19, 1947, Ser. No. 792,722

19 Claims. (CI. 89-14) This invention relates to means and methods for cooling rapid-fire automatic weapons. To comply with the patent statutes the invention is shown in connection with a standard calibre .50 Browning machine gun. However, vit will be readily apparent that only minor changes in size and 'arrangement of parts will be required to adapt it "to other guns of diiferent calibres but similar fire characteristics.

At the present time, one'of the factors limiting sustained operation of rapid-fire weapons is that caused by overheating of the barrel. The barrel of a machine gun of the type disclosed, without a cooling system, will undergo a rapid rise of temperature after only a relatively short burst. For example, in the gun actually tested, without cooling, the barrel temperature increased from about 100 F. to 350 F., with a burst of only 75 rounds over a period of eleven seconds; audit required '15 minutes thereafter, for the barrel temperature to drop to approximately 225". The possibility of sustained'fire is seriously restricted when only natural cooling, that is, cooling by the ambient air, is relied upon. As a result where sustained fire under such conditions is attempted, even should the gun continue to operate, the resultant overheating limits the useful life of the barrel, and the accuracy and range of the gun.

It is accordingly an object of our invention to provide a mechanism and method for cooling rapid fire automatic guns whereby the rate of dissipation of heatfrom the barrel incident to sustained fire, is greatly increased.

A further object is the provision of a system whereby a cooling liquid is directly and automatically introduced into the gun in timed relation with the'firing thereof whereby the heat of the liquid and its latent heat of evaporation, are utilized in the rapid extraction of heat from the barrel.

A still further object is the provision of a cooling system for guns wherein the rapid extraction and dissipation of heat takes place directly from the bore surface of'the barrel and results in the possibility of more frequent bursts, greatly prolonged life of the barrel, increased average accuracy and range over the life of the barrel, and increased fire power from each battery of guns so equipped.

Another object is the provision of a cooling "system for guns of the type aforesaid, which is relatively simple, reliable and easy to operate and which may be readily adapted to all conditions in which such guns are now employed.

Other objects and advantages will become apparent after a study of the following description inconnection with the accompanying drawings wherein:

Fig. 1 shows a side elevation of a standard tripodmounted calibre .50 Browning machine gun'equipped with one form 'ofmy invention,

Fig; 1a is a perspective view of the loadingiand' extracting mechanism of a .50 caliber Browning machine Fig; 2' is a vertical section to an enlarged scale, taken 2,942,524 Patented June 28, 1960 Fig. 3' is a detail elevational view of the lower portion ofFig. Zandv taken atright angles to Fig. 2 show the nozzle guide means,

Fig. 4 is a detail perspective View of the .fluid'cpntrol valve and solenoid operating means depicted upon Fig. 1,

Fig. 5 is a detail substantially full-size elevation of'the left'side of the gun as in Fig; 1, showingthe control switches for energizing and de-energizingthe respective solenoids,

Fig. 6 tea wiringidiagram 'showing'the control circuits for the solenoids", j

Fig; 7 is a detail "sectional elevation of amodification in whichasinglesol'enoid is used. to actuatethenozlzl'e and the fiuid'valve'controlling the same,

Fig. 8i'is a detail sectional view taken upon aplane iiidicated' by line il -8, Fig. 7,

Fig. 9'isia'detailsectional viewtoan enlarged scal,'.of a modified form of Fig. 7 in which thepiston of the valve moves instead of the cylinder thereof,

Fig. 10is a side elevationof a calibre .50 Browning machine gun equipped'with a pivoted type. nozzle and mechanical connections for oscillating the same from the bolt mechanism of the weapon, I I

Fig. .11 isa plan view correspondingto" Fig. 10'showin-g schematically the solenoidcperated control valve and circuit therefor,

Fig. 12 is a plan view,'partly'in section, of amodified form of switch or commutator section, v

Fig; 13 is an elevation looking tromthe right, offth'e modification of Fig. 12,

Fig. 14 is'a vertical section to an enlarged 'scale,'th'rough the 'receiverof a machine gun equipped with an oscillating type nozzle having its control valve formed as an integral part thereof and showing the nozzlenearingjits uppermost, or ejecting position,

Fig; 15 is an elevation taken in a plane'indicated by the line 15--15','Fig; 14,

Fig; 16 isa central vertical section takenup'on a plan indicate'd'by the line 16*16,- Fig. 14, and

Fig: 17 is a detail elevation of the nozzle and operating connections thereto detached'from the gun and'as seen from the right, Fig.14. p

In" Fig. 1 a standard calibre .50 Browning machine gun l'such' as that disclosed in Patent 1,628,226, granted May 10, 1927, is shown swivelled upon a tripod '2. The tripod includes a spiderii to which a pair of rearwardlyextending. legs 4 are detachably connected. A forwardlyextending leg Sis connected with the spider 3""by a plate 6 and an adjustable pivot 7. A central, generally l J- shaped bracket 8'rises centrally from.- s'pider 3 andis pivoted thereon for movement about a normally vertical axis. The receiver 9 ofgun' 1, is journaled at its forward lower side, between the ends of the bracket 8, for'pivotal movement about a normally horizontal axis, as indicated at 10-. The gun is thus mounted for universal pivotal movement. The tripod mounting'shown' is purely conventional and any other wellknown supporting means may be substituted therefor. The gun receiver 9 has been identified. Other standard elements of this weapon may be briefly identified-as 11, barrel; 12, barrel jacket; 13, extractor switch; 14, bolt-stud; and 15, receiver slot. Fig. la shows'the loading and extracting mechanism'of a-0.50caliber Browning, machine gun: The operation of the parts illustrated is so well known as to need abrief description only. The loading or'feeding mechanism includes the beltfeed lever, belt'fc'ed pawl and the'belt holding pawl whereby a'live roundis placedin th'e'jgm and positioned .so'the extractor can draw the round fiojmi the belt (not'shownlend insert it into'the boltslot e, (not shown). As the bolt recoils the live round is pushed into the bolt slot ejecting the spent round from the receiver,through anopening'in the bottom thereof.

" The operation of the Browning is well known and the foregoing brief description is given only to aid in 1 understanding my invention hereinafter disclosed;

limited and regulated by a screw 57 positioned to abut,

lever 51 when the plunger-has moved the piston of valve 43 to fully open position.

' nected with lever 51 by a connecting rod 58' comprising A U-shaped bracket 20 is rigidly secured to receiver '9 in a planejust rearwardly of the breech of barrel 11. As bestshown at Fig. 2, the bracket supports a solenoid 21'betwcen its intermediate portion 21a. and the receiver.

' A pair of guides22 and.23 are secured to the respective .slot' 24 and 25; respectively.

Aplunger Y'identifiedat 26 ,is mounted for reciprocation centrally'within solenoid 21. This plunger is a compositeelement including a section of pipe 27 of magnetic material having abrass nozzle 28 threaded and I brazed, as at '29, to itsupper end. Nozzle 28 is closed I v at its upper end andis provided, closely adjacent such end, with a vent 30. This vent faces toward the breech of barrel 11 and the'parts are so dimensioned that when plunger26 is at its upper limit of travel vent 30 is closely adjacent and in alignment withthe bore of the barrel.-

The lower end-of section 27-is threaded and carries,'first 'a'lock' nut.31 to adjustably limit the upper travel of plunger 26 byabutment .against the bight portion of a yoke 59 having a stud 60 threaded into'a second yoke 61. A bolt 62 pivotally connects rods 45 and 58. A bolt 63 pivotally-connects the other end of rod 58 with lever 51. Thus; as. coil .49 is energized the piston of valve 43 is movedto connect inlet 46 with outlet 47 and cooling fluidis forced through hose 38' and plunger 26,.and ejected from holein the form of a stream or spray.

The coils or'solenoids 21 and 49, are preferablyconnected in series and means are provided for energizing them in timed relation with firing of the gun so that (-1) the nozzle 28 is moved. upwardly into fluid-ejecting position only during the short period when the bolt mechanism is in retracted position and (2) pressure fluid is ejected from the nozzle only when the nozzle is in a position suchthat hole 30 is inalignment withthe bore. I

of the barrel.

' V 1, For the purpose ofcont rolling theicircuit in timedrelation-with firing. of the gun, I have utilized the fact. that extractor switch 13 is moved downwardly, as the bolt:

, the firing of each round. A, metallic stud 64, Figs. 1 and 5, is rigidly attached to switch 13 and projects freelyi through anaperture 65 formed in theleft side of the re.-

ing fit in slots 24 and. 25,. respectively. A compression coil spring -37 surrounds plungers. 26 andacts between 'guide 32 and bracket 20 to urge the plunger into itsv lowermost-or fully retracted position. Downward move-,

ment is limited 'by'engagement of pins 35 and 36 against 1 the ends of the slots 24 and 25. A'section of flexible hose 38 has one end connected to the lower end of a nipple'41, by clamp 39. Nipple-41 isrigidly connected .with pipe'section 27 as by threading and soldering.

Thus, when solenoid 21 is energized, the plunger 26 is drawn upwardly until opening or vent 30 is immediately behind the bore of the barrel so that fluid ejected there- .from is sprayed into the bore to effect cooling of the bore surface, as indicated at 30a, Fig. 2.

A control valve assembly, generally indicated at 40,

Figs. 1 and 4, is carried by one upright of bracket 8."

Referring more particularly to Fig. 4, this assembly in- ,cludes a bracket 42 having its vertical portion 42a adapted to' be rigidly attached to bracket 8. A valve cylinder 43 is fixed to portion 42a by a base 44. Rod 45 is connected to a piston, not shown, within cylinder 43. This piston has a circumferential groove in such a position that,

when the piston is in uppermost position, it acts to connect an inlet pipe 46 to an outlet pipe 47 while acting to cut off the flow of pressure fluid when moved downwardly a short distance depending upon the axial width of the groove or channel. It will be understood that inlet 46 is connected by flexible hose 16 and clamp 17, with any suitable source of coolant, under pressure.

A strap 48 is bolted to the horizontal or shelf portion of bracket 42 and supports a second solenoid 49 provided with a plunger 50 adapted to be drawn upwardly when the solenoid is energized. The forked lower end of plunger 50 embraces one end of a lever 51 and is engages the lever 51 and limits its clockwise movement as viewed in Fig. 4. Upward movement of plunger 50 is assembly of. the gun moves rearwardly subsequently to ceiver. The stud 64 forms one part of a control switch,

generally identified at 66, Figs. 4 and 5; vThe remaining components of this switch may comprise a right-angle bracket 67 adjustably secured to the receiver 9 by screws 68 passing through horizontal slots 69'. The'outstanding.

portion of bracket 67, carries a series of three stacked blocks of insulating material 69. A pair of spring switch f blades or leaves 70 and 71 are held in upwardly-extending spaced relation by block 69iand screws 72 which pass "throughialignedholes in the blocks, leaves and-bracket 67. The. holes in bracket 67 accommodating-screws 72, ,may be elongated vertically whereby to permit limited vertical adjustment of the switch leaves relatively to stud 64. The upper ends of leaves 70 and 71 are bent outwardly and the spacing is such that when stud 64 is moved electn'callyinsulated from the gun bolt.

downwardly, it contacts both leaves and thereby closes a circuit therethrough.

For a purpose subsequently described, a second or auxiliary switch is provided, indicated generally at 73, Figs. 5 and 6. This switch includes insulating blocks 74 and 75 fixed by screws 76 and 77 to the side of receiver 9, upon opposite sides of bolt slot 15. A bowed metallic spring leaf 78 is secured at its ends to the under side of block 74. Likewise a second spring leaf 79 is attached at its ends to the upper side of block 75 and in spaced relation with leaf 78. Bolt stud 14 is attached to, but This stud,

0 therefore moves back along slot 15 as the fired shell is extracted from the barrel and, in so doing, rides between 3 and electrically connects leaves 78 and 79.

' 80 and 81 are connected in parallel with the primaries T82 and 830i transformers 84 and 85. Secondary 86 of transformer 84, has one terminal connected by lead 37, with the anode of electric valve 88 which may be a gridcontrolled mercury vapor tube or Thyratron, such as the FG33. Likewise, one terminal of secondary 89 of transformer 85, is connected by lead 90 with the anode of a second valve 91. The remaining terminals of secondaries 86 and 89 are connected to a common terminal 92 which is connected by lead 93 with one terminal of nozzle control coil 21. The remaining terminal of coil 21 is directly connected by lead 94 to one terminal of coil 49 whose remaining terminal is connected over lead 95 with the common cathode terminal 96 of tubes 88 and 91. Fila- Piston rod 45 is conand a resistor 104 with terminal 102.

inent current for the tubes issupplied from a transformer 97' over'leads 98-and 99. The primary of transformer 97 maybe-supplied from-thesame source as 82 ancl '83.

The grid of tube 88 is connected by lead 100=anda resistor 101, to -a terminal 102 connected withswitch leaf 71'. The grid of tube 91 is connected over lead 103 Resistors .101 and -104'are of about 500' ohms each. The terminal 96 is connected by way of lead 105, contacts-106 of relay 115, and lead 107 with the negative side of a source of- DC. potential 108, having its positive side connectedto switch leaf 70. Thus, with contacts 106' closed, movement of stud'64 downwardly closes control switch-66' andapplies the necessary potential to fire tubes 88'and'91 and'eifect simultaneous energization of coilsor solenoids 21 and 49. This causesmovement of nozzle or plunger element '27 upwardly to position opening30' in alignment with the barrel bore, and connects hose 38 with inlet-46 whereby cooling liquid is sprayed into the barrel. The leaves of switch 66 are so adjusted that they are contacted by stud:64 only during the final two or two and one-half inches of travel of the bolt, at which time the bolt and empty cartridge case are out of the path of movement of nozzle28. During the final quarter-inch of travel of the bolt, extractor switch 13; snaps upwardly to its normal position as a-lug on the extractor overrides the end of the. switch. This acts to open switch 66 andde-energize 'coils 21. and 49 whereupon spring 37 causes/nozzle 28 to. snap downwardly out of the. path of thereturning bolt, while spring: 55 moves valve 43 to fluid cutoff position. The system shown is intended to use water as thezprincipal element'of the coolant at: about. 60 p.s.i.

gage pressure.

In the gun shown, the switch stud 64 moves downwardly for aninstant as the bolt returns to firing position and the extractor moves up on the extractor cam preparatory to feeding in a new cartridge; The duration of this -;movement is very brief but is'long enough to again; energize coil 21 and force injector 28 up against the bottom of the bolt as it moves into forward limiting '109 is connected by a lead 113 withthe-coil 114 of relay 115. The remaining terminal of.coil'114 is connected by lead 116 to a source of potential, not shown. The.

circuit may be completed by a lead 117 extendingfrom the aforesaid source to terminal 110.

It will be noted that switch leaves 78' and 79 are: so positioned relatively to slot 15 and the travel of bolt stud 14, that the latter electrically connectsthe leaves only when the stud is in its forward position of travel. When so connected, the coil 114 is energized to attract the arma-v ture of relay 115 and open the common lead 105 forminga part of the grid circuits of both tubes 88 and 91. Since it is desired to energize coils 21 and. 49 only when the bolt stud 14-is at the rearward'portion-of its travel, auxiliary switch 73 is open at such time, relay 115 is de-energized, and closure of control switch 66 is effective to fire the tubes. However, as stud 14 reaches the forward portion of its travel it acts to close switch 73 and thus open the grid circuit at 106. Consequently when undesired closure of switch 66 takes place due to the momentary movement of switch 13 as aforesaid, such closure is ineffective to close the grid circuit and coils 21' and 49 remain de-energized. Hence'the nozzle 28 and-valve 43 are actuated only when the breech of the barrel: is open and unobstructed.

' At Fig; 7 is shown a simplified form of the invention wherein the coolant control valve and injection nozzle are combined, into a unitary structureand are actuated by a single coil. Referring in detail to this figure, the

. (see Figure 8).

140 inthe lower end of cylinder 124; The stem is threaded I elongated-l U shaped bracket 118 has its upper ends rigidlyattached toopposite sides of the receiver as indicated at 119 and 12t), A solenoid 121 is mounted between the sides'of bracket 118 -to fitsnugly against the under side of the receiver and is supplied by' current from a plug 122, and socket 123 fixed to one side of the bracket.

A valve cylinder 124 fits'smooth'lybetween the sides of bracket 118, Fig. 8, and'is'guided for reciprocation thereon by pairs oflugs such as 125 and 126', each-pair engaging opposite edges of the bracket. At its top, the cylinder has a projection 127 within-which is threaded the lower end of plunger or nozzle element 128 comprising a pipe section 129 ofmagnetic material and a nozzle section 130 united in aligned relation with section-129 by threading and/ or welding. Section 130 which may be of brass has an outlet opening'131' adjacent its upper closed end and so positioned that when the composite nozzle and cylinder are moved to uppermost position, opening 131 lies substantially in the bore axis of the barrel, as indicated at 131a, Fig. 7. This position may be determined by engagement of flange 129a on section 129, against the underside of coil 121;

Cylinder 124-is formedwith an internalcircumferential groove 132 adjacent-its lower end. A passageway 133 places this groove incomrnunication with the bore of section .129. inorder to equalizefluid pressures upon the two sides of. piston 134, a passageway139 is provided in thecylinder wallconnectingi the cylinder ends.

A stem 135 is%fixed1topiston1134 and hasan axial passageway- 136' communicating with radial j bores .137 13% Stem. 13-5 projects through: a' gland at its lower end. This end passes: through'an: aperture in;the,-l1o=rizo-ntal portion. 11801 of" bracket: 11% and is adjustably fixed to thebracket by nuts'141: and142i The end of a flexible hose 1 13 isclamped to stem-135-bya clamp 144. This hose corresponds withhosesl, Fig; l.

A coil spring145 acts between the-lower sideof coil 121 and the top oficylinder 124m urge the latter into lowermost, or cut-off position.

Coil 121 may be energized by the same circuit connections and mechanism" as are used'to'energize coils21 and 49, shown: at Fig. 6. and previously described. Hence itis deemed unnecessary to repeat the description. It is. desired to point. out however, that energizationof the coil 12|1:maybecontrolled by other parts'ofthe gun moving in-tirned relation with the'firing thereof; so long as such. parts have a definite relation or position with respect to. the receiver at the instant that thebreech is free. of wobstructions.

The operation of this form of the invention: will be obvious. Ascoil 121is energized, plunger-128 is drawn upwardly and ejection begins as soon as groove or channe17132 begins to overlap the radial bores in piston134 and thereafter continues as long as the solenoid is energized. As soon as the solenoid is de-energized, spring 145 acts to restore the plunger and cylinder to retracted cut-0E position. By adjustment of nuts 141'and142, the time of ejection and cut-off may be precisely varied with relation to the movement of that part of the gun used to control energization of coil 121. By making bracket 11% in the form of a cylindrical casing, this modification may be completely enclosed so that there areno external moving parts. In such case lugs 125 an'd 126 will ride in axially-extending grooves in theinner wall of the casing.

Fig. 9 shows a modification corresponding generally to the species of Figs. 7 and8, in which the piston of the valve is connected with the nozzle. Inthis' form, a cylinder 146, has an internal circumferential channel 147 in communication with the radial bore 148 of-anipple 149;. The cylinder is closed at its lower end by a'threaded cap 150 having a'central guide 150a. A passageway 151 7 connects the two ends of the cylinder to equalize pressures on the, two sidesof piston 152. Thispiston has a' circumferential groove 153 which communicates by radial bores 154 with a bore 155 in a stem 156 rigidly attached to the piston and extending upwardly through a gland 157 in the closed end of cylinder 146. The lowerend of piston 152, as viewed in Fig. 9, has a second stem 158 extending axially therefrom and extending with'a smooth fit into the bore in guide 150a. Stern 156 may form the armature of a coil' similar to 121 and has a nozzle element secured to its upper end for reciprocation in the manner illustrated in Fig. 7. In this respect, stem 156 is analogous to pipe section 129 of Fig. 7. The relation of the parts is such that groove 153 is aligned with channel 147 when Referring to Figs. 10 and 11, the form' of the inven-' tion there shown is applied to a standard Browning machine gun of the same type as that shown in Fig. 1. Consequently it will be sufiicient to identify barrel 11; jacket 12' and receiver 9". A hollow shaft 159, extends between and is journaled as by means of bearings 160 and 161, in the side walls of receiver 9" on an axis below and substantially in the plane of the breech end of barrel 11'. One end of shaft 159 is closed by a cap 162, while the other end is connected, by clamp 163,

with a flexible hose 164.

A curved or hooked nozzle 165 is fixed to the central portion of shaft 159 and has its passageway 166 in communication with that of the shaft. The shaft is so positioned that in one limiting position, the nozzle tip is aligned with the bore of barrel 11' in position to direct a stream of coolant thereinto, while in the other limiting position the nozzle is entirely below and clear of the barrel.

A coil spring 185-acts to urge the valve element onto its seat 186 in a manner obvious from inspection of Fig. 11.

The circuit for energizing coil 182 in timed relation with loading and firing of the gun comprises a commutator-type switch including a part fixed to shaft 159. The switch element consists of a disc of dielectric ma- .terial 187 having a conducting insert 188. A brush or ,spring contact blade or segment 189 is fixed at one end to an insulating block 190 which, in turn,,is attached to a bracket 191 bolted to the side of receiver 9". The free endof blade 189 bears resiliently upon disc 187 as the latter oscillates with shaft 159. Disc 187 may be fixed to shaft 159 by means such as a set screw, not shown, so thatit can be fixed thereon in any desired position of rotative adjustment. This adjustment is effected so that blade 189 contacts insert 188 at the instant the nozzle 165 reaches injection position behind the breech of barrel 11.

The switch thus provided is included in a circuit for energizing valve coil 182 and shown schematically upon Fig. 11. This circuit may be traced from one pole of source 192 of current by way of lead 193 to one terminal of coil 182 and from the other terminal of said coil by lead 194, to blade 189, thence to segment 188 and by lead 195 to source 192. Thus, as bolt stud 14' approaches its limit of rearward travel, at the instant whenv the breech is clear of the bolt and the extracted cartridge casing, nozzle 165 reaches its injection position, segment 188 moves beneath the end of blade 189, Land the, circuit is closed to energize coil 182. Energization of coil 182 raises valve element 180 from its seat, against the thrust of spring 185, and coolant is forced from the source connected to hose 178, through hose 164, hollow shaft 159 and nozzle 165, into the barrel. As the bolt moves forwardly, the nozzle is pivoted downwardly out of its path, the circuit is broken, and spring 185 closes the valve to cut off further injection.

'At Figs. 12 and 13, I have shown a modified form of commutator or switch element which may replace element 187 in the species shown at Figs. 10 and 11.

A short lever 167 is fixed to the lower end of shaft 159, as viewed in Fig. 11, and has its end pivotally connected by bolt 168, to one end of a link 169. The other end of link 169 is pivoted by bolt 170 to a lever or rocker arm 171 fulcrumed at 172 to a plate 173 bolted to the side of the receiver just forwardly of slot 15'. The end of arm 171 remote from pivot 170, has a slot 174 in which rides a stud 14' attached to the bolt assembly of the gun. As a result of these connections, reciprocation of stud 14' causes a synchronous rocking of shaft 159 through an angle of approximately 90. In the position shown at Fig. 10, the bolt is in its limiting position of rearward translation and arm 171 is consequently in its limiting position of counterclockwise movement and has pivoted shaft 159 and nozzle 165 counterclockwise, into injecting position. As bolt stud 14' moves forwardly, arm 171 and nozzle 165 are pivoted clockwise until the nozzle is entirely clear of the breech. The curved forward portion 17412 of slot 174 acts to slow down pivotal movement of arm 171 for a given travel of stud 14' as the latter approaches fulcrum 172, and limits further angular movement of shaft 159 after the latter has moved to a position in which it has turned nozzle 165 out of the way of the bolt.

The other end of hose 164, is connected by clamp 175 with the discharge nipple of an electro-magnetically operated valve 176 whose inlet 177 is connected by hose 178 and clamp 179 with a source of cooling fluid under pressure. A valve element 180 has a stem 181 of magnetic material forming the armature of an electro-magnet 182. into the valve housing and provided with a gland 184.

This magnet is mounted with a sleeve 183 threaded In these figures, 159 identifies a hollow shaft which may be a duplicate of shaft 159, Figs 10 and 11. A flanged collar 196 has a smooth fit on shaft 159' and may be secured thereon in adjusted position by a set screw 197. A disc 198 of dielectric material is mounted on collar 196 and secured to the flange thereof by one or more screws 199. A second dielectric disc 200 is mounted on collar 196 and is adjustably fixed to disc 198 by screws 201 and 202 which pass loosely through respective arcuate slots 203 and 204 in disc 200 and are threaded into apertures in disc 198. The disc 198 has a conducting segment 205 fixed in its periphery. A like segment 206 is fixed to the periphery of disc 200.

I The contact blade has its end extending over and in contact with the periphery of both discs, as indicated at each from a common lead 195'.

Thus, the total angle of rotation of the commutator during which the valve circuit remains closed, may be varied by loosening screws 20]. and 202, and angularly shifting disc 200 relatively to disc 198, to thereby vary the angular spacing of the remote edges of the segments 205 and 206. Furthermore, by loosening set screw 197, the two discs and collar may be angularly adjusted as a unit to vary the instant at which injection begins. In this way, the period of injection and its timing relatively to the nozzle, may be varied to give the most efiicient cooling. 9 l

In Figs. l4to 17, inclusive, I have shown a rotary or. oscillating type injection nozzle in which the control valve is structurally integrated with the nozzle itself.

ne a es Referring in detailtothesefigures,the receiver 9" has a.-.-fr.ame. or. bracket comprising two sections 213 and5214, attached to respective sides of the receiver, as indicated at,.208 and .209, and secured together at their lower portion, .by a bolt 207. Section, 213has. a bearing aperture 210 in. alignment with a similar aperture 211. in section 214. I

The casing 212 of a valve comprises a body portion having a reduced central projection 212a journaled'in aperture 210. The other end of-casing 212' is closed by a cap215 secured in place by screws 216 and -havirig .a. reduced central projection jo'urnaled in aperture 211.. The casing is thereby mounted for pivotal movement about anaxis 217, Fig. 14.

A nozzle 218 has the same general form as 165, Figs. and 11, and is rigidly attached to casing 212.to extend radially thereof, as by a threaded connection 219, Figs. ,14 and 16. The passageway 22lljin nozzle 218 communicates with the interior-of. the casing through a radial aperture 221 in the casing wall.

The piston element of the valve comprises a core 222 having a smooth fit with casing212and provided; at one endwith an ,axial stem 223 journaled within the bore. in

projection 21%,- and at its vother end with a. hollow stern 224 having a smooth fit within the central hole in cap 215.. A packing gland 225 acts to prevent the escape of fluid under pressure between. the bearing surfaces of cap 215. andstem 224. The end of stem 2214.is threaded, as at- 226, to-provide for connection thereto of a source offlcooleint under pressure.

The. axial passageway .227 in stem 224 and'core 222, communicates with a diametrical bore 288 vin the, core. Bore228 is slightly enlarged at its vends as. clearly indicatedtuponFigs. 14 and 16. To provide a balance of lateral. forceswith. consequent ease of operation of the valve, a .passageway 229; Fig. 14",is providedin the walliof .casing .212,f extending from an interior opening in the .wall'fthereof diametrically opposite aperture 221, extending to.w and opening into said aperture. To balance .axialthrusts on valve .core 222 passageways 23A) and 231,

Fig, 14, are vprovided therein, leading from. bore/228 to the respective ends of the core.

Core .222, and the parts attached, thereto, including stern 224,. are adjustably fixed to. the gun by means ofj a split collan, 232,,adapted. to .be clamped to stem,224 'by bolt 233 in a desired position of "rotary adjustment. An arm 23 4 extends from collar 232 and projects between the confronting ends of adjusting screws 235 ?and' 236, threaded through respective lugs 237and 238on1 bracket section. 214. After a relatively coarse adjustment of core 222 about. axis 217the bolt 233 is tightened and "a final adjustment eiiected by turning of screws 235 and 236 after. which. they are lockedin position bynuts 239..

A stud2 l0 is secured to projection 212a. See Figs. 14

and 17. A lever 241 has its end formed as a split collar 241a.adapte;d.to be clamped inadjusted position to stud- V 240, by bolt 242. An operating link 24$.is pivotally connected with. lever 241, by bolt 24 4. This .link may correspond to link 169; Figs. l0and 11, and be similarly operated by mechanical connection with the bolt action of the gun. Alternatively,.the link may be actuatedby a solenoidsuch as 21, Fig. l, which may be similarly energized, as -in that figure. A spring 245 has one end 'fixed to.casing 212 and its other end to. bracket 213, to urge thecasingand nozzle into retracted position. j

Figs... 14, 15 and 16 show the position of-the parts as I thenozzle is. approaching its limiting position of injection.

Duringfiring, the coolant in bore.228 is at allitimes under pressure. Injection begins the instant that the leading edge ofthe openings of passageways 228'and'229 through the. walLof casing 222, begins to align with passageway 228; andcontinues until such passageways pass out of alignment as the nozzle moves in the reverse direction. In order to give rapid injection and cut-off, the openings 1 ofth'ese passageways throughthe walls of 'casing;212 *and core 222 are somewhat enlarged with straight edges extending in the direction of axis 217, as clearly-shown upon Figs. v.14 and 16; Injection and icut offimay be timed relatively to the position of 'nozzle 218; by adjustment of screws235'and236; The angular" movement of nozzle 218'duringwhich' injection takes place is determined by the circumferential dimension of the ends of, bore 228. Because of the fact that the control valve is an integral part. of ,the nozzle operating mechanism, the amount of coolant and-its momentum between valve and nozzle is a minimum. Consequently, injection and cut-01f are sharp and. the amount of coolant spattered into the gun mechanism, is small. While water is the coolant at present preferred other liquids maybe used such as n-octyl alcohol, benzyl alcohol, diethylene glycol, glyceral, ethylene glycol and ethyl alcohol. Where water is used, various well-known anti-corrosive compounds may be added to preventcorrosion when coolant is spattered into the voperatingnrechanism of the gun.

I 'have shown the system as operating from the breech end of the weapon. It is also contemplated that the cooling nozzle' and its moving means may be attached to the muzzle of the weapon and operated in timed relation with firing, as disclosed,to align the projecting opening therein, into alignment with the bore of the barrel, to eject coolant thereinto. I In fact, from a purely technical point of view, muzzle injection has been found practical, and may, in some cases at least, be preferable to breech injection, since it enables a somewhat greater period of injection vbetween rounds. Where muzzle injection is employed, the supply tube may berfixed to the barrel to extend therealong, and means will be provided to balance all acceleration forces having components normal to the bore axis.

For example, in the form shown at Figs. 1 to 6, inclusive, bracket 2-0 and parts carried thereby, may be clamped .to the. muzzle of the gun with pipe 38 in the form of a small metallic tube, extending along the barrel from valve so. The. remaining parts may be mounted exactly as shown upon Figs. 1 to 6. When rotary valve means are employed, as in the species of Figs. 14 to 17, for muzzleinjection, it will be advantageous to mount the valve .on the barrel at the muzzle, and to oscillate casing 212 in timed relation with firing, by a solenoid or coil operating means carried directly by bracket 213 obvious or readily occur to those skilled in the art, after a study of the present disclosure. Hence I do not wish to be limited to the precise details of constructions shown and f such constructions should be taken as illustrative, rather than in a limiting sense. It is my intention and desire to reservev all modifications andsubstitutions of equivalents Within the scope of the subjoined claims.

Having now fully disclosed the invention, what I claim andjdesire to secure by Letters Patent is:

1. In a cooling system for a rapid fire automatic gun havinga barrel, a nozzle carried by said gun and movable from a first position in which its vent is directed into the bore of said barrel adjacent the breech thereof, to a second position. in which said nozzle is out of alignment with said barrel, means operated in timed relation with firing of said gun to move said nozzle between said first movement laterally of said barrel so that a coolant ejection opening in said nozzle means is moved into and out and means responsive to movement of said part to so move said nozzle means and operate said valve in timed relation with the firing of said gun.

3. In a cooling system for a rapid fire gun having a barrel and loading and extracting means including a part movable in timed relation with said loading and extracting means, a nozzle, first means mounting said nozzle on said gun for reciprocation radially of said barrel closely adjacent one end thereof, conduit means, including a valve adapted to connect said nozzle to a source of coolant under pressure, a first coil adapted, when energized, to move said nozzle so that a coolant ejection opening therein is aligned with the bore of said barrel, a second coil adapted, when energized, to open said valve, circuit means including switch means for energizing said coils, and means operated by said part for closing and opening said switch means in predetermined timed relation with operation of said loading and extracting means.

4. In a cooling system for a rapid-fire gun having barrel and loading and extracting means including a reciprocable bolt assembly and an element oscillating twice in response to each complete reciprocation of said bolt assembly, a hollow plunger, means carried by said gun mounting said plunger for reciprocation radially of said barrel so that a vent opening therein is in and out of alignmentwith the bore of said barrel adjacent the breech thereof, a first coil surrounding said plunger and energizable to move said opening in one direction into alignment with said bore, spring means urging said coil for opening said valve, spring means urging said valve to closed position, a circuit including said coils,

and the anode-cathode of an electron discharge tube having a control grid, a second circuit including (1) the grid of said tube, (2) switch means closed by a first oscillation of said element and (3) a relay, and a circuit including switch means closed by movement of said bolt assembly to open said relay to prevent closure of said grid circuit by a second oscillation of said element.

5. In an automatic rapid fire gun having a barrel, nozzle means mounted on said gun and movable from a first position in alignment with the bore of said barrel adjacent one end thereof, to a second position out of alignment therewith, operating means moving said nozzle means between said first and second positions, in timed relation with firing of the gun, and valve means responsive to movement of said nozzle means to said first position, for connecting said nozzle means to a source of coolant under pressure.

6. In a rapid fire gun having a barrel, a nozzle mounted upon said gun and having a coolant ejecting opening therein, means operated in timed relation with firing of said gun to move said nozzle so that said opening is in and out of aligned relation with the bore of said barrel, and means coupling said nozzle to a source of coolant under pressure only when said opening is in said aligned relation.

7. In a cooling system for a rapid fire gun having a barrel and automatically operating loading and extracting mechanism, a nozzle, means mounting said nozzle for movement into and out of alignment with said barrel at the breech thereof, means including a valve adapted to connect said nozzle with a source of coolant under pressure, and means responsive to movement of said mechanism to move said nozzle into aligned position with said barrel and simultaneously to open said valve, whereby coolant is injected into said barrel.

8. In a direct injection cooling system for an automatic gun, a coil, nozzle means forming an armature for .said coil, bracket means adapted to mount said coil and plungeron said gun so that said nozzle means is in a first position free, of the breech of said barrel when said coil is d'eenergized and in asecond position, with its vent aligned with said barrel, when said coil is energized, two-part valve means mounted on said bracket means, one said part being directly attached to said means to said first position, and connections adapted to connect said valve means to a source of coolant under pressure, said valve being opened only by movement of said nozzle means to said. second position.

9. In a direct-injection cooling system fora gun having a barrel, a nozzle, a two part valve, having a first part in direct connection and coolant-conducting relation with said nozzle, means adapted to mount said nozzle and first part for movement as a unit into and out of coolant injecting position with respect to said barrel, said second valve part being fixedly carried by said means and adapted for connection with a source of coolant under pressure, said valve parts connecting said source to said nozzle only when said nozzle is in coolant-injecting position with respect to said barrel, and means adapted to move said nozzle and first part to and from coolant injecting position, in timed relation with firing of said gun.

10. In a direct-injection cooling system for a rapid fire gun having a barrel, a solenoid, a hollow plunger for said lsolenoid having a coolant ejection opening adjacent one end thereof, a valve cylinder directly connected with the other end of said plunger, a piston for said cylinder and having a stem provided with an axial passageway in communication'with a radial bore in said piston and adapted for connection with a source of pressure coolant, bracket means adapted to mount said solenoid, cylinder and 7 piston on said gun adjacent one end of said barrel, means guiding said plunger and cylinder for reciprocation transversely of the bore of said barrel between a first position in which said opening is adjacent and directed along the bore of said barrel, and a second position in which said plunger is clear of said barrel, there being an opening in the wall of said cylinder adapted to align with the bore in said piston only when said plunger and cylinder are in said first position.

11. In a direct injection cooling system for a rapid fire gun having a barrel and extractor means, a hollow shaft journaled on said gun adjacent one end of said barrel transversely of the bore thereof, a nozzle fixed with said shaft and having its vent in communication with the interior of said shaft, means responsive to movement of said extractor means for pivoting said shaft between a gun having a barrel and a reciprocable bolt mechanism,

a hollow shaft, a nozzle extending from said shaft transversely thereof and having a vent in communication with the interior of said shaft, means mounting said shaft on said gun at the breech thereof for oscillation on an axis transversely of and offset from the bore of said barrel,

said shaft being pivotable between a first position wherein said vent is directed into said bore, and a second position 'valve only when said shaft is substantially in said first position.

13. In a direct injection cooling system for a rapid-fire gun having a barrel and bolt mechanism for loading and extracting cartridges, a nozzle having an injection vent, means mounting said nozzle on said gun for oscillation about an axis transversely of and offset from the bore of said barrel, said nozzle being pivotable between a first position in which said vent is directed into said bore, and a second positoin in which said nozzle is clear of said bore, conduit means adapted to connect said nozzle with a source of coolant under pressure, said conduit means including a valve, and means responsive to movement of said bolt mechanism for oscillating said nozzle between said positions and for opening said valve mechanism only when said nozzle is substantially in said first position, to thereby inject coolant into said bore.

14. The system recited on claim 13, said last-named means including a switch having a part pivotable with said nozzle, a solenoid for opening said valve, a circuit including said switch element and solenoid, said switch operating to close said circuit when said nozzle is substantially in said first position, and spring means urging said valve to closed position.

15. ,The system recited in claim 13, said last-named means including a switch having a part moved by and in response to oscillation of said nozzle and a second part carried by said gun, conduit means adapted to connect said nozzle with a source of coolant under pressure, and including a valve, a solenoid associated with said valve to open the same in energization, spring means urging said valve to closed position, an electrical circuit including said switch and solenoid, and mechanical means responsive to movement of said bolt mechanism for oscillating said nozzle and switch part to close said circuit and open said valve only when said nozzle has moved substantially into said first position.

16. In a direct injection liquid cooling system for an automatic gun having a barrel and a bolt movable from a first position closing the breech of said barrel to a second loading position clear of the breech of said barrel, an injection nozzle, means carried by said gun and mounting said nozzle for reciprocation from a first position clear of the gun barrel, to a second position to direct a stream of liquid thereinto, a solenoid fixed to the gun, an armature for said solenoid connected with said nozzle, a conduit from a source of liquid under pressure to said nozzle, a valve in said conduit, and means moving said nozzle from first to second position and simultaneously opening said valve, said means including an electric circuit for said solenoid and a switch actuated in response to movement of the bolt to predetermined position.

17. In combination, a gun, a carriage in which said gun is mounted for movements in recoil and counterrecoil, a nozzle carried by said carriage for introducing a cooling medium into the gun, means connecting said nozzle to said carriage for lateral swinging movements into and out of alinement with the bore of the gun, and means operative in response to movement of the gun for swinging said nozzle into alinement with the bore of the gun.

18. In combination, a gun, a carriage in which said gun is mounted for movements in recoil and counterrecoil, a nozzle carried by said carriage for introducing a cooling medium into the gun, means connecting said nozzle to said carriage for lateral swinging movements into and out of alinement with the bore of the gun, means operative in response to movement of the gun for swinging said nozzle into alinement with the bore of the gun, and means operative in response to such movement of the nozzle for supplying cooling medium therefrom into the gun.

19. -In combination with a gun of the type in which ammunition is automatically loaded from a magazine associated therewith at the conclusion of each firing operation, a nozzle through which cooling medium is introduced into the bore of the gun, means mounting said nozzle for lateral movements into and out of alinement with the bore of the gun rearwardly of the breach end of g l the gun while the gun is in battery, means operative-in response to movement of the gun for swingingsaid nozzle into alinement with the bore of the gun, means operative in response to such movement of the nozzle for supplying cooling medium therefrom into the gun, and means operative in response to loading of the gun for swinging said nozzle into an inoperative position out of alinement with the bore of the gun.

References Cited in the file of thig patent UNITED STATES PATENTS 783,050 Knapp et al. Feb. 21, 1905 797,237 Smith Aug. 15, 1905 940,101 Wetzel Nov. 16, 1909 1,351,017 Blackmore Aug. 31, 1920 2,416,768 Monner Mar. 4, 1947 2,427,374 Walker Sept. 16, 1947 2,692,533 Finn Oct. 26, 1954 

